故事发生在1890年代的法国,卢梭是一个受人尊敬的法官,当一个退役军人滥杀妇女儿童而遭到逮捕后,法官必须证明那个人不是疯子,他应该对自己的行为负责。然而,法官的道德卫士行径到头来似乎跟杀人凶手一样令人作呕。影片导演的处理和演员的表演都很出色,对人物内心的探索相当犀利,从头至尾都非常引人入胜。France, 1893. Joseph Bouvier, a former Sergeant in the French military, shoots his beloved and attempts to kill himself. Having survived with two bullets in his brain, he is released from the Dole medical facility, a place of mental and physical filthiness. Then begins a five-year period of wandering on the roads of the South East of France, during which Bouvier rapes and eventually kills two dozen defenseless shepherds and farm servants of both sexes. Judge Rousseau thinks this case would help his career as a right wing politician and therefore issues warrants of arrests to find any hobo fitting the description. But if Bouvier was declared insane, the Judge's plan may become a trap...